ML18270A239
| ML18270A239 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 05/25/2018 |
| From: | Indiana Michigan Power Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18270A194 | List:
|
| References | |
| AEP-NRC-2018-17 | |
| Download: ML18270A239 (3) | |
Text
Donald C. Cook Nuclear Plant Commitment Change Summary April 2016 - December 2017 Page 1 of 3 GENERIC LETTER 89-13; SERVICE WATER SYSTEM PROBLEM RESPONSE Commitment No: 1232 Classification: Revision Source Document: AEP-NRC-1104A Existing Commitment Statement:
Periodic cleaning and inspection of safety-related air-to-water heat exchangers will be performed to meet the requirements of GL 89-13.
Revised Commitment Statement:
Periodic cleaning and inspection of safety related air to water heat exchangers will be performed to meet the requirements of GL 89-13. The interval between cleaning and inspection activities may be adjusted to greater than 5 years based on previous inspection results and engineering justification.
Change Description Summary:
Previous inspections of Emergency Diesel Generator (EDG) air aftercoolers indicate the aftercoolers are capable of performing their safety-related function for longer than 5 years without cleaning and inspection. Numerous examinations of the EDG air aftercoolers have revealed no significant fouling, or issues that impact operability.
Donald C. Cook Nuclear Plant Commitment Change Summary April 2016 - December 2017 Page 2 of 3 INCORPORATE STANDARD RADIOLOGICAL SAFETY TECHNICAL SPECIFICATIONS; AMENDMENT NO 53 to DPR-58 AND AMENDMENT NO 39 to DPR-74 Commitment No: 5542 Classification: Revision Source Document: N82044 Existing Commitment Statement:
Also, shutdown procedures have been revised to minimize the time spent in water solid operation of the Reactor Coolant System and a Low Temperature Over Pressure (LTOP) system/ logic has been installed to mitigate over pressure transients. For conditions that do not require opening of the Reactor Coolant System, a low pressure steam bubble will be maintained during the cold shutdown conditions.
Revised Commitment Statement:
Commitment was placed in Retired status.
Change Description Summary:
The intent of the administrative controls described in the commitment (originally included in the 1982 Safety Evaluation for License Amendments that placed LTOP in the Technical Specifications (TS)) was to provide a defense in depth approach to supplement the hardware modification (LTOP) and to limit magnitude of postulated pressure transients to within the bounds of the analysis.
A 2002 Westinghouse InfoGram documents Reactor Coolant Pump (RCP) shaft cracking and propagation for pumps running with the Reactor Coolant System (RCS) in cold conditions.
Cook Nuclear Plant (CNP) pumps are included in the population described; as such the desire is to stop RCPs. Stopping RCPs requires use of Auxiliary Spray from the charging system in order to maintain a low pressure steam bubble in the pressurizer. Use of Auxiliary Spray to maintain a low pressure steam bubble sets up an undesirable situation which results in significant thermal stresses on the pressurizer surge line.
CNP procedures currently require the Site to minimize the time spent in water solid operation, so maintaining a low pressure steam bubble during cold shutdown conditions with no reactor coolant pump operating is not necessary to provide surge volume.
The UFSAR, Revision 26, Chapter 4, for pressurizer PORVs describes the safeguard circuit for LTOP and concludes, This safeguard circuit ensures that the reactor pressure remains below the ASME Section III, Appendix G - Protection Against Nonductile Failure, limits in the case of an LTOP event.
In Section 6.0 of the 1982 Safety Evaluation, the NRC states, Those specific conditions required to assure that the plant is operated within the bounds of the analysis are spelled out in Technical Specifications. Maintaining a low pressure steam bubble in the pressurizer during cold shutdown is not a condition spelled out in CNP TS.
Donald C. Cook Nuclear Plant Commitment Change Summary April 2016 - December 2017 Page 3 of 3 Commitment No: 5542 Change Description Summary (contd):
Considering the factors described above, the requirement to maintain a low pressure steam bubble in the pressurizer is undesirable and not necessary. Since the direction in this commitment to minimize the time spent in water solid operation is duplicated in NRC Commitment 5868 that portion of the commitment is redundant and not necessary. The statement in the commitment that the LTOP system and logic has been installed to mitigate over pressure transients is required by TS and not required to be tracked as a commitment.
Therefore, this commitment was placed in the Retired status.